Zipf is also determined to have his music heard: You may have inadvertently tuned in while driving past him standing at local street corners, thanks to an admittedly hit-or-miss mix of podcasting and podjacking in which Zipf's iPod and small transmitter briefly overwhelm a local radio signal in your car.

Podjacking: the temporary and often impulsive swapping of iPods to
hear what music another person is listening to.

So eavesdropping on Ken's iPod worried me. I have read about people randomly plugging in to each others' iPods to figure out what songs are in their friends' heads, or even in the heads of strangers. (They call it ''podjacking.'')